Detail data pertaining to the shape of an object surface and related methods and systems

Abstract

A method of forming detail data corresponding to a vertex of a polygonal mesh representation of an object surface. The mesh representation has a limit surface, and the vertex has a limit point on the limit surface. The detail data for the vertex relates to the shape of the limit surface near the limit point corresponding to the vertex, and may capture detail about the object surface which is not captured by the mesh representation. The method may involve forming difference or detail data for one or more vertices from the group comprising the vertex in question and one or more neighboring vertices, weighting the resulting difference or detail data with prescribed weights, and deriving the detail data for the vertex in question from the weighted difference or detail data. The difference data for a vertex is the difference between the vertex as mapped onto the object surface and the limit point for the vertex on the limit surface.

What is claimed is:  
     
       1. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of a first object surface, the mesh representation having a limit surface, comprising the following steps: 
       forming difference data corresponding to one or more second vertices of the mesh representation and the first vertex, each converging to a limit point on the limit surface, the difference data corresponding to a vertex formed from the difference between a corresponding point on a second object surface and the limit point of the vertex on the limit surface;  
       assigning prescribed weights to the vertices;  
       weighting the difference data for a vertex with the prescribed weight assigned to that vertex; and  
       deriving the detail data for the first vertex from the weighted difference data.  
     
     
       2. The method of  claim 1  wherein the first vertex is an interior vertex. 
     
     
       3. The method of  claim 2  wherein the mesh representation has one or more levels, and the interior vertex is at an initial level. 
     
     
       4. The method of  claim 2  wherein the mesh representation has one or more levels, and the interior vertex is at a level beyond an initial level and has a valence of six. 
     
     
       5. The method of  claim 1  wherein the prescribed weights are embodied as a stencil. 
     
     
       6. The method of  claim 1  wherein the first vertex is a non-corner boundary vertex. 
     
     
       7. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of a first object surface, the mesh representation having a limit surface, and the first vertex converging to a limit point on the limit surface, comprising the following steps: 
       forming difference data corresponding to the first vertex, the difference data corresponding to the first vertex formed from the difference between a corresponding point on a second object surface and the limit point of the vertex on the limit surface;  
       assigning a prescribed weight to the vertex;  
       weighting the difference data for the vertex with the prescribed weight assigned to that vertex; and  
       deriving the detail data for the first vertex from the weighted difference data.  
     
     
       8. The method of  claim 7  wherein first vertex is an internal vertex. 
     
     
       9. The method of  claim 8  wherein the mesh representation has one or more levels, and the first vertex is at a level beyond an initial level and has a valance other than six. 
     
     
       10. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of a first object surface, the mesh representation having a limit surface, comprising the following steps: 
       forming difference data corresponding to one or more second vertices of the mesh representation, each converging to a limit point-on the limit surface, the difference data corresponding to a vertex formed from the difference between a corresponding point on a second object surface and the limit point of the vertex on the limit surface;  
       assigning prescribed weights to the one or more second vertices;  
       weighting the difference data for a second vertex with the prescribed weight assigned to that vertex; and  
       deriving the detail data for the first vertex from the weighted difference data.  
     
     
       11. The method of  claim 10  wherein the first vertex is a non-corner boundary vertex. 
     
     
       12. The methods of any of claims  1 ,  7  and  10 , wherein the second object surface is the same as the first object surface. 
     
     
       13. The methods of any of claims  1 ,  7  and  10 , wherein the second object surface is different from the first object surface. 
     
     
       14. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of an object surface, the mesh representation having a limit surface, and the first vertex having a limit point on the limit surface, comprising the following steps: 
       assigning prescribed weights to the one or more second vertices of the mesh representation;  
       weighting detail data for a second vertex with the prescribed weight assigned to that vertex, the detail data for a vertex relating to the shape of the limit surface at the limit point for the vertex; and  
       deriving the detail data for the first vertex from the weighted difference data.  
     
     
       15. The method of  claim 14  wherein said forming step comprises forming detail data using any of the methods of claims  1 ,  7  or  10 . 
     
     
       16. The method of  claim 14  wherein said first vertex is a corner vertex. 
     
     
       17. The method of  claim 14  wherein the prescribed weights are embodied as a stencil. 
     
     
       18. A processor readable medium tangibly embodying the methods of any of claims  1 ,  7 ,  10 , or  14 . 
     
     
       19. A system comprising: 
       the processor readable medium of  claim 18 ; and  
       a processor configured to perform the method tangibly embodied on the processor readable medium.  
     
     
       20. A client/server system wherein the client or the server comprises the system of  claim 19 . 
     
     
       21. A memory tangibly embodying the methods of any of claims  1 ,  7 ,  10 , or  14 . 
     
     
       22. A representation of an object surface comprising: 
       a mesh representation of the object surface comprising a mesh of polygons, the mesh representation having a corresponding limit surface; and  
       detail data corresponding to one or more polygonal vertices each converging to a limit point on the limit surface, the detail data for a vertex relating to the shape of the limit surface near the limit point corresponding to the vertex.  
     
     
       23. The representation of  claim 22  wherein the detail data for a vertex relates to the second derivative of the limit surface near the limit point corresponding to the vertex. 
     
     
       24. The representation of  claim 22  wherein the mesh representation comprises a mesh of subdivided or repeatedly subdivided polygons. 
     
     
       25. A processor readable medium tangibly embodying the representation of  claim 22 . 
     
     
       26. A system comprising: 
       the processor readable medium of  claim 25 ; and  
       a processor configured to access the representation tangibly embodied by the computer readable medium.  
     
     
       27. A client/server system wherein the client or the server comprises the system of  claim 26 . 
     
     
       28. A memory tangibly embodying the representation of  claim 22 . 
     
     
       29. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of an object surface, comprising the following steps: 
       a step for forming difference data corresponding to one or more second vertices of the mesh representation;  
       a step for assigning prescribed weights to the one or more second vertices;  
       a step for weighting the difference data for a vertex with the prescribed weight assigned to that vertex; and  
       a step for deriving the detail data for the first vertex from the weighted difference data.  
     
     
       30. A method of forming detail data corresponding to a first vertex of a polygonal mesh representation of an object surface comprising the following steps: 
       a step for assigning prescribed weights to one or more second vertices;  
       a step for weighting detail data for a vertex with the prescribed weight assigned to that vertex; and  
       a step for deriving the detail data for the first vertex from the weighted detail data.  
     
     
       31. A system comprising: 
       medium means for tangibly embodying any of the methods of claims  29 - 30 ; and  
       processor means for performing any of the methods tangibly embodied by the medium means.  
     
     
       32. The methods of any of claims  1 ,  7 ,  10 ,  29  and  30 , wherein the first vertex is a second vertex. 
     
     
       33. The methods of any of claims  1 ,  7 ,  10 ,  29  and  30 , wherein the first vertex is different from the one or more second vertices. 
     
     
       34. A representation of an object surface comprising: 
       mesh representation means for representing the object surface through a mesh of polygons; and  
       detail data means for representing the shape of a limit surface corresponding to the mesh representation means.  
     
     
       35. A system comprising: 
       medium means for tangibly embodying the surface representation of  claim 34 ; and  
       processor means for accessing the surface representation tangibly embodied by the medium means.